1. Field of the Invention
The present invention relates to a receiving apparatus and a receiving method.
2. Description of the Related Art
Digitization of television broadcasts and radio broadcasts has been proceeding on the global scale in recent years. The ATSC (Advanced Television Systems Committee) standards for a terrestrial digital broadcasting system in the United States specifies the following processes: First, signal processing such as Reed-Solomon encoding and interleaving is performed on transport streams (also referred to below as TSs) specified by an international compression coding standard MPEG2 (Moving Picture Experts Group 2). Then, coded modulation is performed by twelve trellis-coded modulators on data on which the signal processing has been performed. Thereafter, the code-modulated data are multiplexed and transmitted in a form of a single carrier wave.
Accordingly, a conventional receiver compliant with the ATSC standards performs synchronous processing and equalization processing on a signal received by a tuner, and then executes twelve trellis decoding processes in parallel on the signal on which the processing has been performed. In this case, the receiver includes twelve identical processing circuits, and therefore circuit size of the receiver is large.
In a technology disclosed in Japanese Patent Publication No. 4113600 (paragraphs 0042 to 0055, FIG. 10 and FIG. 15), a signal group is generated by arranging multiplexed modulation signals cyclically in accordance with the respective trellis-coded modulators that have performed trellis-coded modulation processing. Then, the generated signal group is input to a trellis decoding circuit. The trellis decoding circuit performs traceback processing while identifying in foregoing processing the trellis-coded modulator that has processed the code-modulated signals arranged in the signal group. The technology disclosed in the Japanese Patent Publication proposes the processing described above to configure a receiver with a single trellis decoding circuit.
The technology disclosed in the Japanese Patent Publication, however, requires a memory that can store at least one signal group of cyclically arranged signals and requires the foregoing processing to identify the trellis-coded modulator that has processed the code-modulated signals, thereby increasing required memory capacity and circuit size. This would bring about increased cost of components such as a large-scale integrated circuit (LSI).